Abstract

Synapses exist in different structural forms exhibiting a variety of morphological complexities, which are complimented by a myriad of dendritic spine shapes. This chapter shows how electron microscopy can demonstrate the incredible variety of synapse and spine relationships. It uses both 2-dimensional images and 3-dimensional reconstructions of ultrathin sections of synapses and spines, to illustrate this great variety of morphological forms. The diversity of synapses spines and dendritic structures is also reflected in the nature of their relationships to each other, which far from being on a simple one to one basis, may be very complex either as multisynaptic boutons, or multi-innervated spines. We also examine those structures which can be visualised within both the synaptic bouton and dendritic spine, and the dendrite itself